From c258616badc3fc9aff57b591389cd489767dccd0 Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Fri, 27 Mar 2020 12:33:06 -0700
Subject: [PATCH] Add `Path2D::add_path()`

---
 canvas/src/lib.rs      | 12 ++++++++++++
 content/src/outline.rs | 17 +++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/canvas/src/lib.rs b/canvas/src/lib.rs
index 825055fa..b3204130 100644
--- a/canvas/src/lib.rs
+++ b/canvas/src/lib.rs
@@ -569,6 +569,18 @@ impl Path2D {
         }
     }
 
+    // https://html.spec.whatwg.org/multipage/canvas.html#dom-path2d-addpath
+    pub fn add_path(&mut self, mut path: Path2D, transform: &Transform2F) {
+        self.flush_current_contour();
+        path.flush_current_contour();
+        path.outline.transform(transform);
+        let last_contour = path.outline.pop_contour();
+        for contour in path.outline.into_contours() {
+            self.outline.push_contour(contour);
+        }
+        self.current_contour = last_contour.unwrap_or_else(Contour::new);
+    }
+
     pub fn into_outline(mut self) -> Outline {
         self.flush_current_contour();
         self.outline
diff --git a/content/src/outline.rs b/content/src/outline.rs
index 92033220..659e5f6c 100644
--- a/content/src/outline.rs
+++ b/content/src/outline.rs
@@ -120,6 +120,11 @@ impl Outline {
         &self.contours
     }
 
+    #[inline]
+    pub fn into_contours(self) -> Vec<Contour> {
+        self.contours
+    }
+
     /// Removes all contours from this outline.
     #[inline]
     pub fn clear(&mut self) {
@@ -141,6 +146,18 @@ impl Outline {
         self.contours.push(contour);
     }
 
+    pub fn pop_contour(&mut self) -> Option<Contour> {
+        let last_contour = self.contours.pop();
+
+        let mut new_bounds = None;
+        for contour in &mut self.contours {
+            contour.update_bounds(&mut new_bounds);
+        }
+        self.bounds = new_bounds.unwrap_or_else(|| RectF::default());
+
+        last_contour
+    }
+
     pub fn transform(&mut self, transform: &Transform2F) {
         if transform.is_identity() {
             return;